Composite hydrogen storage material and methods related thereto

ABSTRACT

Embodiments of the invention relate to a composite hydrogen storage material comprising active material particles and a binder, wherein the binder immobilizes the active material particles sufficient to maintain relative spatial relationships between the active material particles.

PRIORITY OF INVENTION

This non-provisional application claims the benefit of priority under 35U.S.C. § 119(e) to U.S. Provisional Patent Application Serial No.60/673,859, filed Apr 22, 2005, which is herein incorporated byreference.

TECHNICAL FIELD

Embodiments of the present invention relate to a composite hydrogenstorage material. Specifically, embodiments of the present inventionrelate to a composite hydrogen storage material for occluding anddesorbing hydrogen.

BACKGROUND

Conventionally, hydrogen may be stored in the form of metal hydridepowders. During the hydriding/dehydriding cycle, strain behavior causesthe particle bed to become unstable, resulting in settling andcompacting of the particle bed. Through repeated cycling, thethree-dimensional relationship of the powder particles continues tochange, causing strain to continue to increase. When using metal hydridepowders, inefficient heat transfer can hamper the rate and effectivenessof the hydriding/dehydriding cycle.

When using traditional metal hydride powders, safety and handling issuesarise as many materials are pyrophoric, or become pyrophoric oncecontacted with hydrogen. In addition, powders may be blown into thehydrogen stream, which requires complicating filtering and alsointroduces a pressure drop into the fuel system.

The hydriding/dehydriding process imparts strain on the storage mediumcausing it to expand during charging and contract during discharge. Thisstrain, which can be quite significant, is conventionally dealt with bydesigning a hydride storage vessel with expansion room to accommodatethe strain. However, the unstable nature of the particle bed causes thepacking of hydride material, effectively filling up the expansion roomand causing significant strain to be exerted on the walls of the storagevessel. Therefore, the storage vessel must be designed to deal with thisinternally induced mechanical strain, either by increasing wallthickness or developing a system of internal structures to cause the bedto ‘unpack’ itself when straining occurs. The need for these complicateddesigns of a storage vessel effectively reduces the volumetric hydrogenstorage density of the metal hydride powders.

The hydriding/dehydriding process causes the powder particles to packmore tightly, thus increasing the compaction of the system. Thethree-dimensional relationship of the particles changes throughout thehydriding/dehydriding cycle, negatively affecting the hydrogen storageability of the powder.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe substantially similar components throughout the several views.Like numerals having different letter suffixes represent differentinstances of substantially similar components. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in the present document.

FIG. 1 illustrates a block flow diagram of a method of making acomposite hydrogen storage material, according to some embodiments ofthe invention.

FIG. 2 illustrates a block flow diagram of a method to occlude anddesorb hydrogen using a composite hydrogen storage material, accordingto some embodiments of the invention.

FIG. 3 illustrates a graphical view of thepressure-composition-temperature (PCT) profile of ahydriding/dehydriding cycle of an exemplary metal hydride hydrogenstorage material, that may be used in some embodiments of the invention.

FIG. 4 illustrates a perspective view of a storage vessel utilizing acomposite hydrogen storage material in communication with a device,according to some embodiments of the invention.

FIG. 5 illustrates a perspective view of a storage vessel utilizing acomposite hydrogen storage material, according to some embodiments ofthe invention.

FIG. 6 illustrates a cross-sectional view of a storage vessel utilizinga composite hydrogen storage material disposed on an interior wall,according to 5 some embodiments of the invention.

FIG. 7 illustrates a cross-sectional view of a storage vessel utilizinga composite hydrogen storage material as a matrix substantially fillingthe storage vessel, according to some embodiments of the invention.

FIG. 8 illustrates a cross-sectional view of a storage vessel acomposite hydrogen storage material as a plurality of layers in a matrixwithin the storage vessel, according to some embodiments of theinvention.

FIG. 9 illustrates a perspective view of a composite hydrogen storagematerial structure, according to some embodiments of the invention.

SUMMARY

Embodiments of the invention relate to a composite hydrogen storagematerial comprising active material particles and a binder, wherein thebinder immobilizes the active material particles sufficient to maintainrelative spatial relationships between the active material particles.Further, embodiments relate to a hydrogen storage system comprising astorage vessel, a composite hydrogen storage material disposed in thestorage vessel, wherein the composite hydrogen storage materialcomprises active material particles and a binder, wherein the binderimmobilizes the active material particles sufficient to maintainrelative spatial relationships between the active material particles andat least one port for communicating with an external device.

Embodiments of the invention relate to a method for making a compositehydrogen storage material comprising forming a fine powder of activematerial particles, mixing a binder with the fine powder to provide amixture and heating the mixture sufficient to form a composite hydrogenstorage material, wherein the binder immobilizes the active materialparticles sufficient to maintain relative spatial relationships betweenthe active material particles. Embodiments of the invention also relateto a method of using a composite hydrogen storage material, the methodcomprising occluding hydrogen onto or within a composite hydrogenstorage material, wherein the composite hydrogen storage materialcomprises active material particles and a binder, wherein the binderimmobilizes the active material particles sufficient to maintainrelative spatial relationships between the active material particles anddesorbing hydrogen from the composite hydrogen storage material.

DETAILED DESCRIPTION

The following detailed description includes references to theaccompanying drawings, which form a part of the detailed description.The drawings show, by way of illustration, specific embodiments in whichthe invention may be practiced. These embodiments, which are alsoreferred to herein as “examples,” are described in enough detail toenable those skilled in the art to practice the invention. Theembodiments may be combined, other embodiments may be utilized, orstructural, and logical changes may be made without departing from thescope of the present invention. The following detailed description is,therefore, not to be taken in a limiting sense, and the scope of thepresent invention is defined by the appended claims and theirequivalents.

In this document, the terms “a” or “an” are used to include one or morethan one and the term “or” is used to refer to a nonexclusive or unlessotherwise indicated. In addition, it is to be understood that thephraseology or terminology employed herein, and not otherwise defined,is for the purpose of description only and not of limitation.Furthermore, all publications, patents, and patent documents referred toin this document are incorporated by reference herein in their entirety,as though individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated referenceshould be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

Embodiments of the invention provide a composite hydrogen storagematerial and methods related thereto. The composite hydrogen storagematerial allows for the occlusion and desorption of hydrogen in whichthe particle bed packing traditionally caused by decrepitation duringthe hydriding/dehydriding cycle is reduced or eliminated. The compositehydrogen storage material comprises active material particles and abinder, wherein the binder immobilizes the active material particlessufficient to maintain relative spatial relationships between the activematerial particles. The composite hydrogen storage material may deformunder hydriding, but substantially returns to its original shape andmorphology, thus the three-dimensional relationships between the activematerial particles are essentially unchanged throughout multiplehydriding/dehydriding cycles.

The composite hydrogen storage material also may act as a load bearingmember within a storage vessel, effectively increasing the volumetricenergy storage of the vessel. By utilizing the composite hydrogenstorage material of the embodiments of the invention, requirements forfiltration of loose metal hydride particles in the desorbed hydrogenstream is eliminated and the traditional problems of powder compactionin metal hydride storage vessels are eliminated. The composite hydrogenstorage material is more thermally conductive than traditional metalhydride powders and retains similar absorption/desorption rate andcapacity limits. The use of a composite hydrogen storage material forhydrogen storage is safer than traditional metal hydride powders asthere is much less risk of storage vessel rupture due to powdercompaction. Further, the use of a composite hydrogen storage materialfor hydrogen storage may allow for better compliance with national andinternational regulatory laws and procedures regarding the transport ofhydrogen and hydrogen storage vessels.

Definitions

As used herein, “composite hydrogen storage material” refers to activematerial particles mixed with a binder, wherein the binder immobilizesthe active material particles sufficient to maintain relative spatialrelationships between the active material particles.

As used herein, “relative spatial relationships” refers tothree-dimensional relationships between particles. Suchthree-dimensional relationships between particles in the context of thepresent invention will remain substantially unchanged. For example, thedistance between particles may change during the hydriding/dehydridingcycle, but the particles return to substantially the same positionrelative to the other particles over the course of one complete cycle.The particle structure may have, e.g., an elastic property, in that theparticles may move, but maintain substantially the samethree-dimensional positioning substantially relative to other particlesas they move. An exemplary indicator of whether a material meets theabove characteristics is a qualitative measurement based upon, e.g., thevolume, packing density or porosity or a dimension (e.g. length) of thecomposite material over repeated cycles. As such, when length of theformed composite is used as the indicator, the length of the formedcomposite will be at least about 80% and not more than about 120% of theparent length measured.

As used herein, “occlude” or “occluding” or “occlusion” refers toabsorbing or adsorbing and retaining a substance. Hydrogen may be thesubstance occluded, for example. A substance may be occluded chemicallyor physically, such as by chemisorption or physisorption, for example.

As used herein, “desorb” or “desorbing” or “desorption” refers to theremoval of an absorbed or adsorbed substance. Hydrogen may be removedfrom active material particles, for example. The hydrogen may be boundphysically or chemically, for example.

As used herein, “immobilize” refers to the holding of particles, suchthat relative spatial relationships are maintained. For example, activematerial particles may be immobilized, allowing them to move, butkeeping the particles substantially in the same geometric relationshipto one another throughout multiple hydriding/dehydriding cycles.

As used herein, “metal hydride particles” or “metal hydrides” refer tometal or metal alloy particles that are capable of forming metalhydrides when contacted with hydrogen. Examples of such metal or metalalloys are LaNi₅, FeTi, Mg₂Ni and ZrV₂. Such compounds arerepresentative examples of the more general description of metal hydridecompounds: AB, AB₂, A₂B, AB₅ and BCC, respectively. When bound withhydrogen, these compounds form metal hydride complexes, such as MgH₂,Mg₂NiH₄, FeTiH₂ and LaNi₅H₆, for example. Examples of metals used toform metal hydrides include vanadium, magnesium, lithium, aluminum,calcium, transition metals, lanthanides, and intermetallic compounds andsolid solutions thereof.

As used herein, “active material particles” refer to material particlescapable of storing hydrogen or to material particles that may occludeand desorb hydrogen, such as metal hydrides, for example. The activematerial may be a metal, metal alloy or metal compound capable offorming a metal hydride when in contact with hydrogen. For example, theactive material may be LaNi₅, FeTi, a mischmetal, a mixture of metals oran ore, such as MmNi₅, wherein Mm refers to a mixture of lanthanides.The active material particles may occlude hydrogen by chemisorption,physisorption or a combination thereof. Active material particles mayalso include silicas, aluminas, zeolites, graphite, activated carbons,nano-structured carbons, micro-ceramics, nano-ceramics, boron nitridenanotubes, palladium-containing materials or combinations thereof.

As used herein, “porosity” refers to the ratio of void space in a volumeto the total volume (1-volume density).

As used herein, “packing density” refers to the efficiency with whichthe active material is packed. Packing density is the percentage of thetotal composite volume that is taken up by the active material. Forexample, a composite with a packing density of about 50% and a porosityof about 40% would consist of about 50% active material, about 10%inactive material, such as binders or additives, and about 40% voidspace by volume.

As used herein, “fine powder” refers to a powder comprising particleswith a small size. For example, the fine powder may substantially becomprised of particles sized below about 100 microns. The fine powdermay be substantially comprised of particles sized below about 50microns, about 10 microns, about 1 micron or about 10 nanometers, forexample.

Referring to FIG. 1, a block flow diagram of a method 100 of making acomposite hydrogen storage material is shown, according to someembodiments of the invention. Active material particles may be formed102 into a fine powder. A binder may be mixed 104 with the fine powdersufficient to create a mixture. The mixture may be heated 106 sufficientto form a composite hydrogen storage material, wherein the binderimmobilizes the active material particles sufficient to maintainrelative spatial relationships between the active material particles.

Active material particles may be comprised of material particles thatare capable of storing hydrogen or of material particles that occludeand desorb hydrogen. Metal hydrides are examples. Examples may be LaNi₅,FeTi, Mg₂Ni and ZrV₂. The active material particles may form 102 a finepowder. The fine powder may be formed 102 by milling, for examplechemical milling, ball milling, high energy ball milling, or jetmilling, or grinding, or by atomizing liquid metals to form smallparticles, or combinations thereof, for example.

The fine powder may be mixed 104 with a binder, such as a thermoplasticbinder. Examples of suitable binders include polypropylene,polyethylene, polyvinylidene fluoride (PVDF), hexaflouropropylenevinylidene fluoride copolymer, cross-linked copolymers,polytetrafluoroethylene (PTFE), perfluoro alkoxy (PFA), thermoplasticpolyesters (for example, NylonTM). If a thermoplastic binder is used,the binder may be readily melt-processable and may have an elongation tobreak of at least about 20%, for example. The amount of binder may beabout 50% by weight or less of the mixture. The binder may be flexibleenough to withstand the charging/discharging (hydriding/dehydriding)strain, while not melting or softening during the elevated temperaturesof the charging phase.

The mixture may be heated 106 to form a composite hydrogen storagematerial. The composite hydrogen storage material produced may have aporosity from about 0.1% to about 50%, for example. The compositehydrogen storage materialg may have a porosity of about 5% to about 40%or from about 15% to about 25%, for example. The packing density of theactive material into the metal hydride composite may be no less thanabout 40%, for example. The packing density may be from about 45% toabout 90%, from about 60% to about 80% or greater than about 70%, forexample. Optionally, the composite hydrogen storage material may undergopressure treatment. The compression pressure may be from about 0.2 MPato about 1000 MPa, or from about 100 MPa to about 400 MPa. In addition,the mixture may be vibrated as well. A further step may include moldingof the composite hydrogen storage material. Examples of molding includecompression molding, injection molding, extrusion or combinationsthereof. The composite hydrogen storage material may be molded into aspecific shape, such as a prismatic shape, a pellet, a wafer, a disc, afilm, a sheet, a perforated sheet, a rod or combinations thereof

The composite hydrogen storage material can have sufficient structuralstrength with a proper binder to withstand the strain induced bycharging and discharging the active material particles without causingthe composite to fracture. Structural strength of the composite hydrogenstorage material allows it to be used as a load bearing member that canresist the force exerted by the hydrogen absorbing into the metalhydride particles. Due to this ability to resist the force produced byparticle strain, the composite hydrogen storage material is able toretain its structural integrity and remain as a solid during multipleocclusion and desorption cycles. The composite hydrogen storage materialmay be shaped as pellets, discs, spheres, wafers, rectangular wafers orany porous or geometric shape.

Optionally, the composite hydrogen storage material may be comprised ofadditional ingredients, additives or structures that improve the thermalor mechanical properties of the composite. Examples include graphiteflakes, carbon fibers, carbon nanofibers, carbon nanotubes, polymerfibers, thermal conductive materials, a metal honeycomb/lattice, metalfibers, wire, metal particles, glass fibers, and combinations thereof.Examples of thermally conductive materials are aluminum foil, aluminumhoneycomb, aluminum powder, carbon fibers, carbon flakes and similarmaterials. Examples of structural additives include carbon flakes,carbon nanotubes, fibers of fiberglass, carbon fibers, carbon nanofibersand combinations thereof. A lubricant may be an example of an additive.A portion of the composite hydrogen storage material may optionally beremoved during manufacture in order to expose such additional materialsas thermally conductive materials and structural additives for example.

Additionally, an adsorbent or absorbent material can be added to thecomposite hydrogen storage material. The adsorbent or absorbent materialmay adsorb or absorb materials toxic to the active ingredient or thatmay interfere with the hydriding/dehydriding process. Some examples mayinclude activated carbon, calcium oxide, other metals that readilyoxidize, or ‘oxygen getters’.

Optionally, a fire retardant may be added to the composite hydrogenstorage material. Suitable specific fire retardants include, e.g.,phosphonium ammonium borate (i.e., phospho-ammonium boron);3,4,5,6-dibemzo-1,2-oxaphosphane-2-oxide or9,10-dihydro-9-oxa-10-phospaphenanthrene-10-oxide (OPC) [CAS RegistryNumber 35948-25-5]; sulfamic acid monoammonium salt (ammonium sulfamate)[CAS Registry Number 7773-06-0]; di-n-butyltin oxide (DBTO) [CASRegistry Number 818-08-6]; di-n-octyltin oxide (DOTO) [CAS RegistryNumber 780-08-6]; dibutyltin diacetate di-n-butyltin diacetate (NS-8)[CAS Registry Number 1067-33-0]; dibutyltin dilaurate di-n-butyltindilaurate (Stann BL) [CAS Registry Number 77-58-7]; ferrocene; ironpentacarbonyl; ammonium sulfate; ammonium phosphate; zinc chloride; andcombinations thereof, for example.

The following are examples of composite hydrogen storage materials andmethods related thereto, according to some embodiments of the invention

EXAMPLE 1

5 grams LaNi₅ powder with a particle size of about 1 micron or less ismixed with 0.2 grams of Atofina's 2851 kynarflex (Polyvinylidienefluoride derivative) grade thermoplastic powder with a particle size ofabout 0.1 micron or less. The mixture is compression molded at about 100MPa and 165° C. in a mold of the desired shape. The mold is then cooledto room temperature while maintaining the 100 MPa of compressionpressure. The resulting part released from the mold is a porous solidcomposite with about 28% porosity, a mass of 5.2 grams, a specificgravity of about 5.2, and a LaNi₅ packing factor of about 60%.

EXAMPLE 2

5 grams LaNi₅ powder with a particle size of about 1 micron or less ismixed with 0.2 grams of graphitic flakes with a particle size of about1-10 microns and with 0.2 grams of Atofina's 2851 kynarflex(Polyvinylidiene fluoride derivative) grade thermoplastic powder with aparticle size of about 0.1 micron or less. The mixture is compressionmolded at 100 MPa and 165° C. in a mold of the desired shape. The moldis then cooled to room temperature while maintaining the about 100 MPaof compression pressure. The resulting part released from the mold is aporous solid composite with about 28% porosity, a mass of 5.4 grams , aspecific gravity of about 5.0, and a LaNi₅ packing factor of about 56%.The addition of the graphitic flakes increases the strength and thermalconductivity of the composite solid. These improved properties arebeneficial to improve the rate of hydrogen charging and the structuralintegrity of the part.

EXAMPLE 3

5 grams LaNi₅ powder with a particle size of about 1 micron or less ismixed with 0.2 grams of Polyparaphenylene terephthalamide (Kevlar)fibers about 10-20 microns in diameter/ about 1-2 mm long and with 0.2grams of Atofina's 2851 kynarflex (Polyvinylidiene fluoride derivative)grade thermoplastic powder with a particle size of about 0.1 micron orless. The mixture is compression molded at about 100 MPa and 165° C. ina mold of the desired shape. The mold is then cooled to room temperaturewhile maintaining the 100 MPa of compression pressure. The resultingpart released from the mold is a porous solid composite with about 28%porosity, a mass of 5.4 grams , a specific gravity of about 4.9, and aLaNi₅ packing factor of about 53%. The addition of the Polyparaphenyleneterephthalamide fibers increases the strength of the composite material

EXAMPLE 4

5 grams LaNi₅ powder with a particle size of about 1 micron or less ismixed with 0.2 grams of activated carbon with a particle size of about1-10 microns and with 0.2 grams of Atofina's 2851 kynarflex(Polyvinylidiene fluoride derivative) grade thermoplastic powder with aparticle size of about 0.1 micron or less. The mixture is compressionmolded at 100 MPa and 165° C. in a mold of the desired shape. The moldis then cooled to room temperature while maintaining the about 100 MPaof compression pressure. The resulting part released from the mold is aporous solid composite with about 28% porosity, a mass of 5.4 grams , aspecific gravity of about 4.8, and a LaNi5 packing factor of about 52%.The activated carbon serves to adsorb harmful compounds that mayotherwise contaminate the metal hydride during charging.

Referring to FIG. 2, a block flow diagram of a method 200 to occlude anddesorb hydrogen using a composite hydrogen storage material is shown,according to some embodiments of the invention. A composite hydrogenstorage material 202 may be placed in a storage vessel 204 to create acomposite hydrogen storage material-vessel structure 206. Hydrogen maybe occluded 208 onto or within a composite hydrogen storagematerial-vessel structure 206 sufficient to produce a composite hydrogenstorage material-vessel structure storing hydrogen 210. The hydrogen maybe desorbed 212, which readies the composite hydrogen storagematerial-vessel structure 206 for another cycle of hydrogenabsorption/desorption. The absorption/desorption of hydrogen may berepeated numerous times, up to about 10,000, or up to about 100,000 forexample, depending on the hydride material used.

A composite hydrogen storage material 202 may be placed in a storagevessel 204, such as a tank or container. As an example, the compositehydrogen storage material 202 may be utilized in a cellular fuel tanksuch as discussed in Zimmermann, U.S. Provisional Patent ApplicationSer. No. 60/757,782 (Attorney Docket No. 2269.004PRV), entitled“CELLULAR RESERVOIR AND METHODS RELATED THERETO,” filed Jan. 9,2006, thedisclosure of which is incorporated herein by reference in its entirety.

Because of its structural strength in solid form, the composite hydrogenstorage material 202 serves the dual function of storing hydrogen andalso of holding the hydrogen storage particles in a fixed relativespatial relationship. Therefore, the function of resisting the straininduced by the charging of hydrogen onto the material is fulfilledentirely by the composite hydrogen storage material. As a result, thevessel for storing the hydrogen 210 need be designed to resist only thegas pressure of the system.

Referring to FIG. 3, a graphical display of the absorbing/desorbingcharacteristics of an exemplary hydrogen storage material within astorage vessel is shown. FIG. 3 shows a graphical view of thepressure-composition-temperature (PCT) profile of ahydriding/dehydriding cycle of a metal hydride hydrogen storagematerial, such as one which may be used in some embodiments of theinvention.

Referring to FIG. 4, a perspective view of a storage vessel utilizing acomposite hydrogen storage material in communication with a device 400is shown, according to some embodiments of the invention. The storagevessel 410 comprises an external wall 408, an optional pressure relieffunctionality 406, and port 404 in which to communicate with an externaldevice 402. The optional pressure relief functionality 406 may be apressure relief mechanism, such as a valve, a spring loaded-valve, afusible trigger, a rupture disk, a diaphragm, or a vent feature, whichmay be integral to a tank. The port 404 may be a sealable port, forexample. The external device may be a fuel cell system, a hydrogensource, a heat pump, a hydrogen compressor, or air conditioning system,for example. External device 402 may also be a gas management device,such as a regulator, check valve, on/off valve or other interconnection,for example. Alternatively, a portion of one of the exterior walls 408may comprise a fuel cell layer, fuel cell system, a hydrogen source, aheat pump or a hydrogen compressor, for example.

When used in conjunction with a fuel cell, it is possible to create acompact system for powering portable electronic devices. Some examplesof portable electronics for use with the fuel cell include, but are notlimited to, cellular phones, satellite phones, laptop computers,computer accessories, displays, personal audio or video players, medicaldevices, televisions, transmitters, receivers, lighting devicesincluding outdoor lighting or flashlights, electronic toys, or anydevice conventionally used with batteries.

The storage vessel 410 may be of a small size and the optional pressurerelief functionality 406 may be integrated into the design of thestorage vessel 410. For larger storage vessels 410, a pressure activatedrelief device or temperature activated relief device may be usable. Theactivation temperature range may be from about 150° C. to about 400° C.for a temperature activated relief device. For a pressure activatedrelief device, the activation pressure may be from about 200 to about1000 psi, but will depend on the thickness and strength of the storagevessel 410 walls.

Referring to FIG. 5, a perspective view of a storage vessel 500utilizing a composite hydrogen storage material is shown, according tosome embodiments of the invention. The storage vessel 500 comprises anoptional pressure relief functionality 504 and port 506. Pressure relieffunctionality 504 is optional and may be eliminated from the design ofthe storage vessel, particularly when the vessel is very small, or hasbeen designed with an integral feature to fail while allowing reasonablysafe relief of internal pressure. The port 506 may be used tocommunicate with any number of external devices (not shown in figure).

Referring to FIG. 6, a cross-sectional view of a storage vessel 600utilizing a composite hydrogen storage material disposed on an interiorwall is shown, according to some embodiments of the invention. Thestorage vessel 600 comprises an interior wall 606 and exterior wall 602.A composite hydrogen storage material 604 may be disposed within theinterior wall 606, creating a space 608 between the composite hydrogenstorage material 604 and interior wall 606. The composite hydrogenstorage material 604 may be in the form of matrix which may utilize amelt processible polymer, for example polyvinylidene fluoride,polyethylene or polypropylene, as the binder. The matrix may partiallyor entirely fill the interior space of the storage vessel 600.

The composite hydrogen storage material 604 may be optionally adhered toat least a portion of at least one of the interior walls 606 of thestorage vessel 600. The composite hydrogen storage material 604 may beadhered using a melt processible polymer, for example. Alternatively,adhering may be performed by gluing the composite hydrogen storagematerial 604 to at least a portion of at least one of the interior walls606. An example of glue that may be utilized is an epoxy adhesive or asilicone adhesive, for example.

Referring to FIG. 7, a cross-sectional view of a storage vessel 700utilizing a composite hydrogen storage material as a matrixsubstantially filling the storage vessel is shown, according to someembodiments of the invention. The storage vessel 700 comprises aninterior wall 706 and exterior wall 702. A composite hydrogen storagematerial 704 may be disposed as a matrix within the interior wall 702,substantially filling the storage vessel 700.

Referring to FIG. 8, a cross-sectional view of a storage vessel 800utilizing a composite hydrogen storage material as a plurality of layersin a matrix within the storage vessel is shown, according to someembodiments of the invention. The storage vessel 800 comprises aninterior wall 810 and exterior wall 802. A composite hydrogen storagematerial 804 can be disposed as a plurality of layers within theinterior wall 802, creating spaces 806. Between each layer of thecomposite hydrogen storage material 804, may be placed an optionalconductive member 808. During the manufacture of the composite hydrogenstorage material 804, portions of the structure may be removed in orderto expose a conductive member 808.

For example, a storage vessel 800 may be filled with composite hydrogenstorage material 804 so that storage vessels 800 of differing sizes maybe built up from the same basic element. This would allow for theplacement of composite hydrogen storage material 804 with othermaterials inside the storage vessel 800, i.e. placing heat conductingmembers around the composite hydrogen storage material 804, as shown.Some of the material may then be removed to expose parts of thecomposite 804 that have particular characteristics, such as exposingheat conducting members 808 embedded within the material.

Referring to FIG. 9, a perspective view of a composite hydrogen storagematerial structure 900 is shown, according to some embodiments of theinvention. A composite hydrogen storage material structure 900 can beformed in such shapes as a rectangular wafer 902, for example. Thecross-sectional cut out illustrates the interaction of active material904, such as a metal hydride, and binder 908, which may create one ormore interstitial spaces or voids 906. The spaces 906 allow for hydrogendiffusion and flow through the active material, such as metal hydrideparticles so that hydrogen is able to reach the interior of the formedcomposite hydrogen storage material.

While the present invention has been particularly shown and describedwith reference to preferred embodiments, it will be readily appreciatedby those of ordinary skill in the art that various changes andmodifications may be made without departing from the spirit and scope ofthe invention. It is intended that the claims be interpreted to coverthe disclosed embodiment, those alternatives which have been discussedabove and all equivalents thereto.

The Abstract is provided to comply with 37 C.F.R. § 1.72(b) to allow thereader to quickly ascertain the nature and gist of the technicaldisclosure. The Abstract is submitted with the understanding that itwill not be used to interpret or limit the scope or meaning of theclaims.

1. A composite hydrogen storage material comprising: active materialparticles; and a binder; wherein the binder immobilizes the activematerial particles sufficient to maintain relative spatial relationshipsbetween the active material particles.
 2. The composite hydrogen storagematerial of claim 1, wherein the active material particles are capableof occluding and desorbing hydrogen.
 3. The composite hydrogen storagematerial of claim 1, wherein the active material particles occludehydrogen by physisorption, chemisorption or a combination thereof
 4. Thecomposite hydrogen storage material of claim 1, wherein the activematerial particles comprises a metal hydride.
 5. The composite hydrogenstorage material of claim 1 wherein the active material particlescomprise type AB, AB₂, A₂B, AB₅, BCC metal hydrides or combinationsthereof.
 6. The composite hydrogen storage material of claim 1, whereinthe active material particles comprises LaNi₅, FeTi, or MmNi₅, whereinMm refers to a mixture of lanthanides.
 7. The composite hydrogen storagematerial of claim 1, wherein the active material particles comprisesilicas, aluminas, zeolites, graphite, activated carbons,nano-structured carbons, micro-ceramics, nano-ceramics, boron nitridenanotubes, palladium-containing materials or combinations thereof
 8. Thecomposite hydrogen storage material of claim 1, wherein the binder isthermoplastic.
 9. The composite hydrogen storage material of claim 8,wherein the thermoplastic binder is selected from the group ofpolypropylene, polyethylene, polyvinylidene fluoride,hexafluoropropylene vinylidene fluoride copolymer, cross-linkedcopolymers and combinations thereof.
 10. The composite hydrogen storagematerial of claim 1, further comprising one or more additives.
 11. Thecomposite hydrogen storage material of claim 1, further comprising athermally conductive additive.
 12. The composite hydrogen storagematerial of claim 11, wherein the thermally conductive additivecomprises aluminum, graphite flakes, graphite fibers, or a combinationthereof
 13. The composite hydrogen storage material of claim 1, furthercomprising an adsorbent additive.
 14. The composite hydrogen storagematerial of claim 13, wherein the adsorbent additive is capable ofadsorbing materials that can interfere with the hydrogen storingfunction of the active material particles.
 15. The composite hydrogenstorage material of claim 13, wherein the adsorbent comprises activatedcarbon.
 16. The composite hydrogen storage material of claim 1, furthercomprising a structural additive.
 17. The composite hydrogen storagematerial of claim 16, wherein the structural additive is selected fromthe group of carbon flakes, carbon nanotubes, fibers of fiberglass,carbon fibers, carbon nanofibers and combinations thereof.
 18. Thecomposite hydrogen storage material of claim 1, further comprising afire retardant.
 19. The composite hydrogen storage material of claim 1,further comprising a lubricant.
 20. A composite hydrogen storagematerial comprising: active material particles; a binder; and one ormore additives; wherein the binder immobilizes the active materialparticles and one or more additives sufficient to maintain relativespatial relationships between the active material particles and one ormore additives.
 21. A composite hydrogen storage material comprising:active material particles; and a binder; wherein the composite hydrogenstorage material comprises a porosity from about 0.1% to about 50%, andwherein the active material particles comprise a packing density that isat least about 40% of the composite hydrogen storage material.
 22. Ahydrogen storage system comprising: (A) a storage vessel; (B) acomposite hydrogen storage material disposed in the storage vessel,wherein the composite hydrogen storage material comprises: activematerial particles; and a binder; wherein the binder immobilizes theactive material particles sufficient to maintain relative spatialrelationships between the active material particles; and (C) at leastone port for communicating with an external device.
 23. The hydrogenstorage system of claim 22, wherein the external device is a fuel cellsystem, a hydrogen source, a heat pump, a hydrogen compressor, a valveor a pressure regulator.
 24. A method for making a composite hydrogenstorage material comprising: (A) forming a fine powder of activematerial particles; (B) mixing a binder with the fine powder to providea mixture; and (C) heating the mixture, sufficient to form a compositehydrogen storage material, wherein the binder immobilizes the activematerial particles sufficient to maintain relative spatial relationshipsbetween the active material particles.
 25. The method of claim 24,further comprising after heating the mixture, applying pressure to thecomposite hydrogen storage material.
 26. The method of claim 24, furthercomprising after heating the mixture, applying vibration to thecomposite hydrogen storage material.
 27. The method of claim 24, furthercomprising after the grinding, mixing an additive with the binder andthe fine powder.
 28. A method of using a composite hydrogen storagematerial, the method comprising: (A) occluding hydrogen onto or within acomposite hydrogen storage material, wherein the composite hydrogenstorage material comprises: active material particles; and a binder;wherein the binder immobilizes the active material particles sufficientto maintain relative spatial relationships between the active materialparticles; and (B) desorbing hydrogen from the composite hydrogenstorage material.
 29. The method of claim 28, further comprising afterdesorbing hydrogen, occluding hydrogen onto or within a compositehydrogen storage material a second time.
 30. The method of claim 29,further comprising after occluding hydrogen onto or within a compositehydrogen storage material a second time, desorbing hydrogen from thecomposite hydrogen storage material a second time.
 31. The method ofclaim 30, further comprising after desorbing hydrogen from the compositehydrogen storage material a second time, occluding hydrogen anddesorbing hydrogen three or more times, up to about 100,000 times. 32.The method of claim 31, wherein the active material particlessubstantially maintain spatial relationships between the active materialparticles during the occluding hydrogen and desorbing hydrogen up toabout 100,000 times.